Anti-Aspiration Prosthesis

ABSTRACT

A prosthesis and a method of manufacturing the prosthesis for controlling flow through a bodily lumen are provided. The prosthesis includes a body having a proximal portion, a distal portion and a lumen extending therethrough. The prosthesis also includes a valve operably connected to the body. The valve has a proximal portion, a distal portion and a lumen extending through the valve, where the valve lumen is connected to the body lumen. The valve is configured to be closed in the absence of an antegrade pressure and a retrograde pressure, the retrograde pressure being greater than the antegrade pressure. The valve includes a material portion operably connected to the valve, the material portion providing increased stiffness to the valve relative to the valve alone, wherein the material portion is configured to facilitate self-reversion of the valve to the closed configuration.

RELATED APPLICATIONS

This application is continuation of U.S. application Ser. No.15/059,041, filed Mar. 2, 2016, which is a divisional application ofU.S. application Ser. No. 13/790,640, filed Mar. 8, 2013 (now U.S. Pat.No. 9,314,325), which claims the benefit of U.S. Provisional ApplicationNo. 61/639,217, filed Apr. 27, 2012, which are incorporated by referenceherein in their entirety.

FIELD OF THE INVENTION

The present invention relates to medical devices and in particular to avalve for regulating fluid flow therethrough.

BACKGROUND OF THE INVENTION

The lower esophageal sphincter (LES) in healthy individuals allows foodto pass into the stomach, but prevents gastric fluids from moving intothe esophagus except when the patient vomits. Aspiration is a clinicalrisk for patients having a malfunctioning LES or for patients havingstents placed across the gastroesophageal junction (GEJ) so that anopening is created at the bottom of the esophagus that can lead to acidreflux and aspiration. Aspiration occurs when the stomach contentstravel from the stomach into the lungs. Aspiration in the lungs can leadto pneumonia or death. Risk of aspiration in patients having acompromised LES increases when the patient is in a prone position.

Anti-reflux esophageal prostheses or stents have been developed to treattumors or strictures in the vicinity of the LES. Anti-reflux esophagealprosthesis or stent is typically placed in the lower esophagus andthrough the LES to maintain the patency thereof due to the presence of acancerous tumor commonly found in the vicinity thereof or to treatbenign tumor conditions, such as blockage or strictures.

A problem with an esophageal prosthesis or stent is that fluid from thestomach flows into the mouth of the patient when in a prone position,increasing the risk of aspiration. In an attempt to solve the problem, anumber of esophageal prostheses or stents utilize a one-way valve suchas a duck-bill or reed-type valve in which only food or fluid from theesophagus flows into the stomach in only an antegrade or forwarddirection. However, these one-way anti-reflux prostheses or stentspresent another problem. When the patient wants to belch or vomit, thepatient is prevented from doing so, because the one-way valve preventsbackward flow in the retrograde direction. Such condition is not onlypainful to the patient, but can also lead to more complicated medicalconditions.

What is needed is a prosthesis that is normally closed to preventgastric fluids from entering the esophagus, allows food to pass into thestomach and also allows for vomiting and belching when necessary andreturns to the closed position.

BRIEF SUMMARY

Accordingly, it is an object of the present invention to provide adevice and a method of manufacturing the device having features thatresolve or improve on the above-described drawbacks.

A prosthesis and a method of manufacturing the prosthesis forcontrolling flow through a bodily lumen are provided. The prosthesisincludes a body having a proximal portion, a distal portion and a lumenextending therethrough. The prosthesis also includes a valve operablyconnected to the body. The valve has a proximal portion, a distalportion and a lumen extending through the valve, where the valve lumenis connected to the body lumen. The valve is configured to be closed inthe absence of an antegrade pressure and a retrograde pressure, theretrograde pressure being greater than the antegrade pressure. The valveincludes a material portion operably connected to the valve, thematerial portion providing increased stiffness to the valve relative tothe valve alone, wherein the material portion is configured tofacilitate self-reversion of the valve to the closed configuration. Insome embodiments, the material portion includes at least one materialthat may be made from a different material than a valve material. Insome embodiments, the material portion may be the same material as thatof the valve but be formed into such a way that enables the valve toself-revert. This can be achieved by using a change in the materialportion relative to the remainder of the valve such as a thickenedportion of valve material which is incorporated into one section of thevalve. This section of material is designed to not possess the sameflexibility as the valve material. Therefore under a certain pressurethe valve inverts however due to the rigid section it quickly revertsback to the preformed shape.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a prosthesis in accordance with an embodimentof the present invention in a closed configuration;

FIG. 2 is a side view of the prosthesis shown in FIG. 1 in an openconfiguration in response to flow in an antegrade direction;

FIG. 3 is a side view of the prosthesis shown in FIG. 1 in an invertedconfiguration in response to flow in a retrograde direction;

FIG. 4 is an end view of a prosthesis in accordance with an embodimentof the present invention;

FIG. 5 is a partial side view of an embodiment of a prosthesis inaccordance with the present invention;

FIG. 6 is a partial side view of an alternative embodiment of aprosthesis in accordance with the present invention;

FIG. 7 is a partial side view of an alternative embodiment of aprosthesis in accordance with the present invention;

FIGS. 8A-8E illustrate alternative embodiments of the material portionof the prosthesis of the present invention;

FIGS. 9A-9C illustrate alternative embodiments of the material portionof the prosthesis;

FIG. 10 is a partial side view of an embodiment of the material portion;

FIGS. 11A and 11B illustrate embodiments for positioning the materialportion around a perimeter of the body of the prosthesis in accordancewith the present invention;

FIG. 12 illustrates an embodiment of the position of the materialportion around a perimeter of the body;

FIG. 13 is a partial side view of an alternative embodiment of amaterial portion;

FIG. 14 is a partial side view of an alternative embodiment of amaterial portion;

FIG. 15 illustrates an embodiment of the material portion;

FIG. 16 illustrates an alternative embodiment of the material portion;

FIG. 17 illustrates an alternative embodiment of the material portion;

FIG. 18 illustrates an embodiment of the material portion positionedon/in the valve;

FIG. 19 illustrates an embodiment of the material portion positionedon/in the valve;

FIG. 20 illustrates an embodiment of the material portion positionedon/in the valve;

FIGS. 21A and 21B illustrate an embodiment of the material portion thatmay be formed from a sheet of material;

FIG. 22 illustrates an embodiment of the material portion that may beformed from a sheet of material;

FIG. 23 illustrates an embodiment of the material portion that may beformed from a sheet of material;

FIGS. 24A and 24B illustrate an embodiment of the material portion thatmay be formed from a sheet of material;

FIGS. 25A and 25B illustrate an embodiment of the material portion thatmay be formed from a sheet of material;

FIG. 26 illustrates an embodiment of the material portion that may beformed from a sheet of material;

FIG. 27 illustrates an embodiment of the material portion that may beformed from a sheet of material;

FIG. 28 illustrates an embodiment of the material portion that may beformed from a sheet of material;

FIG. 29 illustrates an embodiment of the material portion that may beformed from a sheet of material

FIG. 30 illustrates an embodiment of the material portion that may beformed from a sheet of material;

FIG. 31 illustrates an embodiment of the material portion that may beformed from a sheet of material;

FIG. 32 illustrates an embodiment of the material portion having a coil;

FIG. 33 illustrates an embodiment of the material portion having a coil;

FIG. 34 illustrates an embodiment of the material portion having a coil;

FIG. 35 illustrates an embodiment of the material portion having a coil;

FIG. 36 illustrates an embodiment of the material portion having a coil;

FIG. 37 illustrates an embodiment of the material portion having a coil;

FIG. 38 illustrates an embodiment of the material portion having a coil;

FIGS. 39 and 40 illustrate embodiments of the material portion having anundulation;

FIG. 41 illustrates an embodiment of the material portion having a loop;

FIG. 42A-42C illustrate an embodiment of the material portion having acoil;

FIGS. 43A and 43B illustrate embodiments of a retrofit valve; and

FIG. 44 is an illustration of a prosthesis positioned within the loweresophageal sphincter.

DETAILED DESCRIPTION

The invention is described with reference to the drawings in which likeelements are referred to by like numerals. The relationship andfunctioning of the various elements of this invention are betterunderstood by the following detailed description. However, theembodiments of this invention are not limited to the embodimentsillustrated in the drawings. It should be understood that the drawingsare not to scale, and in certain instances details have been omittedwhich are not necessary for an understanding of the present invention,such as conventional fabrication and assembly.

As used in the specification, the terms proximal and distal should beunderstood as being in the terms of a physician delivering theprosthesis to a patient. Hence the term “distal” means the portion ofthe prosthesis that is farthest from the physician and the term“proximal” means the portion of the prosthesis that is nearest to thephysician.

The present invention relates to medical devices, and in particular toprosthetic devices for implantation in a body lumen such as theesophagus, the vasculature, the urinary tract and the biliary tree. Asused herein, the term “implantable” refers to an ability of a medicaldevice to be positioned at a location within a body, such as within abody lumen, either temporarily, semi-permanently, or permanently.Permanent fixation of the device in a particular position is notrequired. Furthermore, the terms “implantation” and “implanted” refer tothe positioning of a medical device at a location within a body, such aswithin a body lumen.

FIG. 1 illustrates a prosthesis 10 in accordance with an embodiment ofthe present invention. The prosthesis 10 includes a body 12 havingproximal portion 14, a distal portion 16 and a lumen 18 extendingtherethrough. In some embodiments, the body 12 may be an expandablestent such as a self-expandable stent or a balloon expandable stent.Non-limiting examples of expandable stents include the Z-Stent® and theEVOLUTION® stent (Cook Medical, Inc. Bloomington, Ind.). In someembodiments, the body 12 may be a non-expandable tubular stent. Theproximal portion 14 of the body 12 may include an end portion 15 havingan expanded outer diameter and the distal portion 16 may include an endportion 17 having an expanded outer diameter. In some embodiments, thebody 12 may be a substantially straight tubular shape. The body 12 mayinclude a coating or a sleeve 22 extending through or around the body 12that is liquid impermeable so that liquid and nutrients flowing from theproximal portion 14 to the distal portion 16 or stomach contents fromthe distal portion 16 to the proximal portion 14 do not pass through awall 24 of the body 12. As shown in FIG. 1, the prosthesis 10 includes avalve 26. In some embodiments, the valve 26 may be contiguous with thecoating or sleeve 22 and in some embodiments the valve 26 may beseparately provided. The valve 26 includes a lumen 30 operably connectedto the lumen 18 of the body 12. The valve 26 is configured to controlfluid flow through the prosthesis 10. The valve 26 may be provided as aformed valve where the valve is formed to be closed to form a protectivebarrier reducing the risk of stomach contents entering the valve 26 inthe retrograde direction, especially when a patient is in a proneposition. The valve 26 includes a material portion 28 that isincorporated into, onto or throughout the valve 26 as will be describedin more detail below. The valve may be any shape. Exemplary shapes areshown and described below.

Referring to the embodiment shown in FIG. 1, the valve 26 is operablyconnected to the body 12 and extends distally from the distal portion 16of the body 12. In some embodiments, a proximal portion 32 of the valve26 is connected to the body 12. A distal portion 34 of the valve 26 isconfigured to extend into the patient's stomach. The valve 26 is shownin a closed configuration 36 in FIG. 1 where a distal end portion 38 ofthe valve 28 is closed upon itself so that stomach contents cannot flowfrom in the retrograde direction from the stomach to the esophagus orlungs of the patient. A first pressure 40 is normally present in stomachand the valve 26 is configured to normally be closed in the presence ofthe first pressure 40 or in the absence of any pressure, for examplewhen the patient is in a prone position.

FIG. 2 illustrates the valve 26 of the prosthesis 10 in an openconfiguration 42 in response to a second pressure 44 that occurs whenliquid and nutrients flow from the mouth and pass to the stomach. Thesecond pressure 44 is greater than the first pressure 40. The nutrientstravel in an antegrade direction 48 through the lumen 18 of the body 12and into the lumen 30 of the valve 26 to the stomach. The distal endportion 38 of the valve 26 opens in response to the second pressure 44to allow flow from the mouth to the stomach. In the absence of thesecond pressure 44, the valve 26 is configured to return to the closedconfiguration 40 shown in FIG. 1.

FIG. 3 illustrates the valve 26 in the open configuration 42 in responseto a third pressure 50 that is greater than the first and secondpressures 40, 42. For example, when the patient needs to belch or vomit,the valve 26 opens in response to the third pressure 50. The thirdpressure 50 pushes at least a portion of the valve 26 proximally toevert the valve 26 so that the distal end portion 38 of the valve 26extends proximally. The valve 26 opens so that the third pressure 50built up in the stomach may be relieved through the mouth. In theabsence of the second or the third pressure 42, 50, the valve 26 returnsto the closed configuration 40 shown in FIG. 1. After the third pressure50 is removed, in some embodiments, the valve 26 may be re-inverted sothat the distal end portion 38 extends distally. In some embodiments,the valve 26 may be re-inverted by the patient swallowing water or bythe material portion 28 returning to its original position.

As shown in FIGS. 1-3, the valve 26 includes the material portion 28that may provide one or more of the advantages described below. Thematerial portion 28 may be provided to introduce a stiffness or rigidityinto the valve 26 that is greater than the stiffness of the valve 26alone. In some embodiments, the stiffness can be introduced withoutneeding to increase the thickness of a wall of the valve 26. In otherembodiments, the thickness of the wall of the valve 26 may also beincreased. The increased stiffness or rigidity added by the materialportion 28 may also facilitate better loading, delivery and recapturingof the prosthesis 10 so that the valve 26 does not become blocked in thedelivery system. The material portion 28 may also help the valve 26 toself-revert and return to closed configuration by providing aspring-like effect so that the distal end portion 38 extends distallyafter the third pressure 50 has been relieved. By way of non-limitingexample, the material portion 28 may be formed of a resilient materialthat springs into shape, such as a shape memory material or a polymerthat may be provided as a wire or a sheet. In some embodiments, thenitinol may be heat set. Other materials are also possible. By way ofnon-limiting example, material may include metal alloys such asstainless steel, tantalum or its alloys, tungsten, platinum, gold,copper, palladium, rhodium, or a superelastic alloys, such as nitinol orpolymers that can be provided with sufficient shore hardness, such asPebax, Peek, polyimide, liquid crystal polymers (LCP) such as Vectran,polyethylene, polyethylene terephthalate and Nylon. In some embodiments,the material may be nitinol and in some embodiments the nitinol may beheat set. In some embodiments, the material portion 28 is made from adifferent material than the valve 26. In some embodiments, the materialportion 28 may be made of the same material as the valve 26. Thematerial portion 28 may be provided at a proximal portion, a distalportion, through the entirety of the valve 26 or at any portion of thevalve 26. In some embodiments, the material portion 28 may be providedon a side of the valve 26.

In some embodiments, the material portion may be formed from heat setnitinol or formed to allow the valve 26 to self-return. In thisembodiment, the material portion 28 comprising the nitinol arm/springmay be attached to an external surface 27 of the valve 26. Once thevalve 26 moves in response to the retrograde flow and the retrogradeflow is stopped, the nitinol arm/spring rapidly pulls the valve 26 backto the original shape of the valve. In some embodiments, the materialportion 28 comprising the nitinol arm/spring may be attached to asurface 35 of the body 12. In other embodiments, the material portionmay be connected to an interior surface of the valve 26 or embeddedwithin the valve 26. In some embodiments, the material portion isconnected to the valve and is not connected to the body 12. In someembodiments, the material portion 28 may be formed from an elastomericmaterial and connected to the valve 26 and/or the body 12 similarly tothe nitinol arm/spring described above. In some embodiments, thematerial portion 28 may be connected to an interior of the body 12.

As shown in the end view in FIG. 4, the material portion 28 may bendinward towards a center 52 of the valve 26 in the presence of the thirdpressure 50 to facilitate the proximal extension of the distal endportion 38 of the valve 26 and the opening of the lumen 30. In someembodiments, a distal end 47 of the material portion 28 may extendacross a portion of the distal portion 16 of the body 12 as shown inFIG. 4. In some embodiments, the distal end 47 of the material portion28 may extend into the lumen 18 of the body 12 as shown in FIG. 3. Thematerial portion 28 may then spring back to its original position wherethe distal end 47 of the material portion 28 extends distally when thethird pressure 50 is relieved which also helps return the valve 26 tothe closed configuration 40.

When the material portion 28 is provided on or in the proximal portion32 of the valve 26, the material portion 28 may be operably connected tothe distal portion 16 of the body 12. As shown in FIG. 5, the materialportion 28 may be connected to a distal end 54 of the body 12 so that aproximal end 56 of the material portion 28 extends distally from thedistal end 54 of the body 12. The entire material portion 28 is free tomove inward in response to the third pressure 50 to facilitate theproximal extension of the distal end portion 38 of the valve 26 and theopening of the lumen 30. In some embodiments, the material portion 28may be directly connected to the distal end 54 and in some embodiments,the material portion 28 may be connected to the valve 26 and the valve26 is connected directly to the body 12. The material portion 28 may beconfigured to extend inward toward the center 52 as shown in FIG. 4.

As shown in FIG. 6, in some embodiments the material portion 28 may beoperably connected to the body 12 at a position proximal to the distalend 54 of the body 12 so that the material portion 28 partially overlapsthe body 12. The material portion 28 may be operably connected to thebody 12 within the lumen 18 or external to the body 12. A distal portion58 of the material portion 28 may move inward in response to the thirdpressure 50 and the distal end portion 38 of the valve 26 may extendproximally and the lumen 30 may be opened. The distal portion 58 of thematerial portion 28 may then spring back to its original position whenthe third pressure 50 is relieved which also helps return the valve 26to the closed configuration 40.

FIG. 7 illustrates an alternative embodiment of the material portion 28.As shown, the material portion 28 may be formed as an extension of thebody 12. For example, when the body 12 is formed as a woven mesh, one ormore ends 60 of the body 12 may be distally extended relative to otherends 61 so that a subset of ends 60 of the body 12 form the materialportion 28. The material portion 28 shown in FIG. 7 may bend and springback to position similar to the embodiments described above.

The material portion 28 may be provided in many different shapes orpatterns. In addition to the pattern shown in FIG. 1, exemplary patternsfor the material portion 28 are shown in FIGS. 8A-8E. By way ofnon-limiting example, the material portion 28 may include the followingshapes or patterns: strips, mesh, diamond, u-shaped, circular, zig-zag,crisscross, v-shaped spring and the like. Additional shapes and patternsare also possible for the material portion 28. Any of the patterns maybe operably connected to the body 12 in accordance with any of theembodiments described above.

The spacing and the positioning of the material portion 28 may also bevaried to change the flexibility of the material portion 28. Forexample, as shown in FIG. 9A, the flexibility of the material portion 28may be varied by increasing or decreasing the length A or by increasingor decreasing the length B that also changes the angle θ at a peak 29 ofthe material portion 28. FIG. 9B illustrates that the material portion28 may be formed from a plurality of independent members 31 that areseparate from each and independently operably connected to the valve 26.FIG. 9C illustrates an alternative embodiment showing that the materialportion 28 may be formed from a continuous member 33 having a pluralityof peaks 29 and operably connected to the valve 26. The shape of themembers 31 and 33 may vary, for example having peaks 29 that are archedor curved. Other shapes for the peaks may also be used.

In some embodiments, the material portion 28 may be formed by a pair ofindependent members 31 a, 31 b at the same position on or in the valve26 as shown in FIG. 10. A plurality of pairs 31 a, 31 b may bepositioned in or on the valve 26 in some embodiments. A first member 31a may be positioned within a second member 31 b and extending along thesame plane. The first and second members 31 a, 31 b may have the sameflexibility or different flexibilities. In some embodiments, the firstmember 31 a may have a thicker diameter and thus be more rigid than thesecond member 31 b. In some embodiments, the first and second members 31a, 31 b may have the same diameter. The flexibility of the materialportion 28 is stiffer closer to the body 12 where four wires of thefirst and second members 31 a, 31 b extend along the same plane. Thematerial portion 28 is more flexible at the distal portion 58 where twowires extend along the same plane.

When the material portion 28 includes a plurality of peaks 29 on acontinuous member 33, the number of peaks 29 may be varied as shown inFIGS. 11A and 11B. The position of the peaks 29 are indicated by numbersshown on the end view of the body 12. As shown in FIG. 11A, four peaks29 may be provided for the material member 28. The peaks 29 may beequidistantly spaced apart around a perimeter 66 of the body 12 or insome embodiments, the spacing between the peaks 29 may be unequal. Insome embodiments, the angle θ of each of the peaks 29 may increase asthe valve 26 expands, for example as food passes through the valve 26.The angle θ of each of the peaks 29 may decrease as the valve 26collapses. Some of the peaks 29 may be configured to resist bending inresponse to the third pressure 50 and some of the peaks 29 may beconfigured to facilitate bending in response to the third pressure 50.These peaks 29 may be alternated to help the valve 26 return to theclosed configuration 40 when the third pressure is relieved.

In some embodiments, the material portion 28 may be formed from twoindependent peaks 29 spaced equidistance apart from each other on thevalve 26 as shown in FIG. 12. The peaks 29 may be connected to the body12 or to the valve 26 similar to the embodiments described above. Thepeak 29 may be positioned so that the peak 29 of the material portion 28extends distally away from the body 12 or extends proximally toward thebody 12. In some embodiments, the material portion 28 may be formed fromone or more straight wires 37 that are operably connected to the valve26 as shown in FIG. 13.

One or more of the peaks 29 of the material portion may be treated sothat a proximal portion 41 of the peak 29 may be more rigid than adistal portion 43 of the peak 29 as shown in FIG. 14. The differencebetween the proximal portion 41 and the distal portion 43 may be usedregardless of the shape of the material portion 28. For example, thewire 37 shown in FIG. 13 may have different flexibilities in theproximal and distal portions 41, 43. By way of non-limiting example, thedifference in flexibility of the material portion 28 may be provided byelectropolishing, chemically etching or grinding the distal portion 43of the material portion 28. FIG. 14 illustrates the difference in thediameter of the proximal portion 41 and the distal portion 43 afterelectropolishing or chemical etching. The more flexible distal portion43 may be helpful in preventing the material portion 28 from damagingthe valve 26.

In some embodiments, the material portion 28 may be provided within thevalve 26 or connected to the body 12. As shown in FIG. 15, the materialportion 28 may include one or more loop portions 72 to facilitate thereturn of the valve 26 to the closed configuration after the retrogradeflow has ceased. FIG. 16, illustrates an embodiment of the materialportion 28 that may include one or more springs or arms 74 that areprovided with the valve 26 to facilitate the return of the valve 26 tothe closed configuration after the retrograde flow has ceased. Thesprings 74 may be coiled and may be provided in any direction, forexample parallel to the axis of the body 12 or perpendicular to the axisof the body 12 or at an angle to the axis of the body 12 or incombinations of directions. FIG. 17 illustrates an alternativeembodiment of the material portion 28 where the material portion 28 iscurved to facilitate the movement of the valve 26 toward the body12/into the body 12 in response to retrograde flow and to facilitate thereturn of the valve 26 to the closed configuration.

In some embodiments, the prosthesis 10 may be provided with a materialportion 28 that is a single arm that is incorporated onto or within thevalve 26 as shown in FIGS. 18-20. The single arm material portion 28 maybe provided on or in any portion of the valve 26. By way of non-limitingexample, the single arm material portion 28 is shown positioned on aflattened face 82 of the valve 26 in FIG. 18. In some embodiments, theface may be an angled face where the arm is formed at the same anglethat the valve is formed so that the material portion 28 fits into thevalve on the angled face. A proximal portion 86 of the material portion28 is shown connected to the body 12 of the prosthesis 10 in FIGS. 18and 19. FIG. 20 illustrates the proximal portion 86 of the materialportion 28 embedded within the valve 28 and unconnected to the body 12.FIGS. 19 and 20 illustrate the single arm material portion 28 positionedon a side 84 of the valve 26 away from the flattened face 82. In someembodiments, the single arm material portion 28 may be generallyu-shaped with a distal portion 88 of the material 28 forming the “u.”The distal portion 88 of the material 28 may be wider than the proximalportion 86. In some embodiments, the distal portion 88 may be the samewidth or narrower than the proximal portion 86. As discussed above, thematerial portion 28 may be positioned on any portion of the valve. Insome embodiments, the material portion 28 may be a single arm and inother embodiments, the material portion 28 may be a plurality of arms asdescribed above.

Additional configurations for the material portion 28 are shown in FIGS.21-42. By way of non-limiting example, the material portion may be madefrom a sheet of material such as nitinol. Exemplary sheet configurationsare shown in FIGS. 21A-25B where the material portion may be formed fromone or more layers of material. FIG. 21A illustrates the materialportion 28 having a first portion 92 that is u-shaped and a secondportion 94 that is operably connected to one or more ends 96 of the “u”so that the distal end 88 of the “u” can fold over on the second portion94 in response to the pressure 50. FIG. 21B shows a side view of theembodiment in FIG. 21A.

FIG. 22 illustrates the material portion 28 formed from a single layerof material that is folded onto itself. The first portion 92 may includea portion 102 that is folded onto itself and that may also include acoil 104. An end 106 of the first portion 92 may bend over the coil 104in response to the pressure 50 and then return the originalconfiguration after the pressure 50 is removed. FIG. 23 illustrates anembodiment similar to FIG. 22 and includes the u-shaped first portion 92and a pair of coils 104. The distal portion 88 is configured to foldover the coils 104 in response to the pressure 50 and then return to theoriginal configuration after the pressure is removed.

FIGS. 24A and 24B illustrate an embodiment of the material portion 28having a pivotable arm. The material portion 28 may be made for one ormore layers of material, such as a sheet of nitinol. The materialportion includes the first portion 92 that may have a u-shapedconfiguration although other shapes are also possible. The first portion92 includes one or more coils 104 and the first portion 92 is configuredto pivot on a fixed shaft 106. The fixed shaft 106 may be connected tothe body 12 of the prosthesis 10. The distal end portion 88 isconfigured to pivot toward the proximal portion 14 of the body 12 (notshown) in response to the pressure 50. In some embodiments, the distalportion 88 may also be flexible and bend toward the proximal portion 86.The material portion 28 is configured to return to the originalconfiguration in the absence of the pressure 50.

FIGS. 25A and 25B illustrate an embodiment of the material portion 28having a plurality of coils 104 so that the distal portion 88 of thefirst portion 92 can fold toward the proximal portion 86 in response tothe pressure 50. The material portion 28 may be made for one or morelayers of material, such as a sheet of nitinol. The material portion 28includes the first portion 92 that may have a u-shaped configurationalthough other shapes are also possible. The first portion 92 includes aplurality of coils 104 and two fixed ends 96. The fixed ends 96 may beconnected to the body 12. The distal end portion 88 is configured tomove toward the proximal portion 14 of the body 12 (not shown) inresponse to the pressure 50. The plurality of coils 104 facilitates themovement of the distal portion 88 toward the proximal portion 86. Insome embodiments, the distal portion 88 may also be flexible and bendtoward the proximal portion 86. The material portion 28 is configured toreturn to the original configuration in the absence of the pressure 50.

FIGS. 26-31 illustrate embodiments of the material portion 28 that maybe formed from a sheet of material. In some embodiments, the sheet maybe a nitinol sheet or other type of shape memory material orcombinations thereof. The sheet may also be a polymer or a combinationof a polymer and a metal or any material have sufficient spring-likecharacteristics. The material portion 28 includes the proximal portion86 and the distal portion. In some embodiments, the distal portion 88may be formed to be thinner relative to the proximal portion 86 toincrease flexibility of the distal portion 88. In other embodiments, theproximal portion 86 may be formed to be thinner relative to the distalportion 88 to increase flexibility of the proximal portion 86. In someembodiments, such as shown in FIG. 27, the distal portion 88 may includean opening 108 to increase flexibility of the distal portion 88. Theembodiment shown in FIG. 27 may also include a thinner distal portion88. As shown in FIGS. 28 and 31, the u-shape at the distal portion 88may have a narrower arm width relative to the ends 92 and/or theproximal portion 86. In some embodiments, the “u” may be wider than theends 96 as shown in FIG. 28 and in some embodiments the “u” may narrowor have an arch shape 110 as shown in FIG. 29. FIG. 30 illustrates anembodiment of the material portion 28 that tapers to a narrower distalportion 88 relative to the proximal portion 86. The embodiment shown inFIG. 30 may also have a thinner distal portion 88 relative to theproximal portion 86 or a thinner proximal portion 86 relative to thedistal portion 88.

FIGS. 32-38 illustrate embodiments of the material portion 28 where thematerial portion 28 may be formed from a wire. The wire may be any kindof wire suitable to flex and return in response to pressure exerted onthe material portion 28. In some embodiments, the wire may be made fromnitinol or other shape memory material, although other materials arealso possible. In some embodiments, the nitinol wire may be heattreated, etched, ground, electropolished or otherwise treated tofacilitate bending in some portions of the wire. The material portion 28may be a u-shaped wire as shown in FIG. 32. Similar to embodimentsdescribed above, the material portion made of wire may have a thinnerwire at the distal portion 88 relative to the proximal portion 86 or athinner wire at the proximal portion 86 relative to the distal portion88.

In some embodiments, the material portion 28 may include one or morecoils 104 as shown in FIGS. 33-38. As shown in FIG. 33, the materialportion 28 includes the coil 104 having a single turn 112. Theembodiment shown in FIG. 33 includes two coils 104, each coil 104positioned distal to the ends 96 and proximal to the u-shaped distalportion 88. FIGS. 34 to 37 show embodiments having increasing numbers ofturns 112 in the coils 104 and FIG. 37 illustrates the turns 112 coiledin a different direction relative to the turns 112 shown in FIGS. 34-36.In some embodiments, the material portion 28 may have a coil 104including 1, 2, 3, 4, 5, 6 or more turns. These embodiments alsoillustrate different dimensions for the u-shaped distal portion 88.

FIG. 38 illustrates an alternative embodiment of the material portion 28that may be formed from a wire. The proximal portion 86 includes thecoil 104 having a plurality of turns 112 that are distal to the proximalend 96. The distal portion 88 of the material portion shown in FIG. 38includes a loop 114. In the embodiments shown in FIGS. 33-38, the coils104 are shown extending generally parallel to the bottom of the “u” inthe distal portion 88. However, the coils 104 may extend generallyperpendicular to the bottom of the “u” in the distal portion 88 as shownin FIG. 42.

FIGS. 39-40 illustrate embodiments of the material portion 28 formedfrom a flattened material that includes one or more undulations 116 inthe proximal portion 86 of the material portion 28. The material may beany of the materials described above. The width and the thickness of thematerial portion 28 may be varied from the proximal portion 86 to thedistal portion 88. FIG. 41 illustrates an embodiment of the materialportion 28 including a plurality of loops 114 at the proximal portion86. The width and the thickness of the material portion 298 may narrowtoward the distal portion 88 of the material portion 28 in someembodiments. FIGS. 42A-42C illustrate an embodiment of the materialportion 28 having a plurality of coils 104 extending generallyperpendicular to the bottom of the “u” of the distal portion 88. Thecoils 104 are shown flexing in response to a pressure exerted on thematerial portion in FIGS. 42B and 42C.

In some embodiments, the valve 26 may be retrofit into an existing body12 of a prosthesis 10 that has already been positioned within apatient's lumen. The retrofit valves may have any of the featuresdescribed and may also include an attachment member to attach the valveto the existing body. As shown in FIGS. 43A and 43B, the valve 26 mayinclude an attachment member 120 that is configured to position thevalve 26 within the body 12 and hold the valve 26 within the body. Theattachment member 120 may be connected to the proximal portion 14 of thevalve 26 as shown, although other attachment positions for theattachment member 120 are also possible. By way of non-limiting example,the attachment member 120 may be provided as an expandable mesh thatexpands to conform to the shape of the lumen of the body 12 into whichthe valve 26 is positioned as shown in FIG. 43 A. In other embodiments,the attachment member 120 may be provided as a plurality of connectors122 that are configured to connect to the stent to hold the vale 26 inposition. Other methods and attachment members may also be used tosecure the retrofit valve 26 to the body 12.

As shown in FIG. 44, the prosthesis 10 may be positioned in the loweresophageal sphincter (LES) 11. The prosthesis 10 may be delivered to theLES using a delivery catheter such as the Evolution delivery system(Cook Medical Incorporated, Bloomington, Ind., not shown) and positionedin the LES. Other types of delivery systems may also be used. Theproximal portion 14 of the body 12 may be positioned proximal to theesophageal sphincter 11. The distal portion 16 of the body 12 may bepositioned so that the distal portion 16 and/or the valve 26 extend intothe stomach 13. As shown, the body 12 extends across a growth 602 thatmay be occluding the esophagus. The valve 26 normally remains closed inthe absence of the second and third pressures 44, 50 described above.

The materials used to manufacture the components of the prostheticdevices described herein may be any materials known to one skilled inthe art that are suitable for use in patients. By way of non-limitingexample, the body may be formed from metals or polymers. Suitableexemplary metals include stainless steel and nitinol and the body may bewoven or provided in a zig-zag configuration. Valves of the prostheticdevices of the embodiments may be made from any suitable biocompatiblematerial that is liquid impermeable and that does not degrade in thepresence of fluids or gastric material that comes in contact therewith.By way of non-limiting example, the valve may be made from a medicalgrade polyurethane material, silicone, nylon, polyamides such as otherurethanes, or other biocompatible materials that are flexible and acidresistant. An exemplary material for the valve is a medical gradepolyurethane material grade EG-80A material commercially known asTecothane®; polyurethane material (Thermedics, Incorporated, Woburn,Mass.) or medical grade silicon. The material portion may be formed froma metal or a polymer. By way of non-limiting example, the materialportion may be formed from nitinol. In some embodiments, the materialportion is made from a different material than the valve. Examples ofsuitable materials include, polymers, such as polytetrafluoroethylene(PTFE), polyurethane, shape memory poly-urethane, and poly-silicone.UHMW Poly-ethylene; elastomeric Poly-ethylene; LD Poly-ethylene; HDPoly-ethylene; Poly-propylene; Elastomeric PTFE; polyethyleneterephthalate (PET); polyethyleneoxide (PEO), and block copolymerscontaining polystyrene and poly(1,4-butadiene), and an ABA triblockcopolymer made from poly(2-methyl-2-oxazoline) and polytetrahydrofuran,amorphous or organic-inorganic hybrid polymers comprising polynorborneneunits and shape memory polymers. In some embodiments, portions of theprosthesis may be radiopaque or may include one or more radiopaquemarkers.

The valve of the embodiments described above may be formed as follows.For example, when nitinol is used to from the material portion, thematerial portion may be formed on a metal mandril in to the desiredshape. The shape is then heat set so the nitinol wants to remain in theset shape. To make the valve, and optionally the coated body, the valvemandril is dipped into a solution, by way of non-limiting example asilicone or a poly-urethane polymer dispersion. In some embodiments, thevalve mandril may be made of PTF, anodized aluminum; glass; Dacron, mildsteel and stainless steel. The polymer dispersion solution provides andinner surface for the valve that is then cured. The heat set nitinolstructure is transferred to the valve mandril on top of the curedpolymer dispersion inner layer. The polymer dispersion layer and theheat set nitinol structure are then dipped again into the polymerdispersion. The shape of the metal mandril and the valve mandril aredifferent so that when the valve is produced, the nitinol tries to forcethe valve into a specific configuration. The axis of the body 12 of awoven stent may be different than the axis of a woven material portion.In some embodiments, the material portion may be suspended into thevalve. In some embodiments, the valve may be formed by anelectrospinning process, using heat shrink tubing, blow molding process,extruding, molding, weaving and heat forming a polymer material over thea mold with the required shape. Any suitable method known to one skilledin the art may be used to form the valve.

The above Figures and disclosure are intended to be illustrative and notexhaustive. This description will suggest many variations andalternatives to one of ordinary skill in the art. All such variationsand alternatives are intended to be encompassed within the scope of theattached claims. Those familiar with the art may recognize otherequivalents to the specific embodiments described herein whichequivalents are also intended to be encompassed by the attached claims.

1. A prosthesis for controlling flow through a bodily lumen, theprosthesis comprising: a body having a proximal portion, a distalportion and a lumen extending therethrough; and a valve operablyconnected to the body, the valve having a proximal portion, a distalportion and a lumen extending through the valve, the valve lumenconnected to the body lumen; the valve being configured to be closed inthe absence of an antegrade pressure and a retrograde pressure, theretrograde pressure being greater than the antegrade pressure, the valvecomprising a material portion operably connected to the valve, thematerial portion providing increased stiffness to the valve relative tothe valve alone, wherein the material portion is configured tofacilitate self-reversion of the valve to the closed configuration. 2.The prosthesis of claim 1, wherein the material portion comprises atleast one material that is different from a valve material.
 3. Theprosthesis of claim 1, wherein the material portion comprises nitinol.4. The prosthesis of claim 3, wherein the nitinol is heat set.
 5. Theprosthesis of claim 1, wherein the material portion is connected to thedistal portion of the body.
 6. The prosthesis of claim 1, wherein thematerial portion at least partially overlaps the body.
 7. The prosthesisof claim 2, wherein the material portion comprises one arm.
 8. Theprosthesis of claim 2, wherein the material portion comprises oneu-shaped arm.
 9. The prosthesis of claim 2, wherein the material portioncomprises a coil.
 10. The prosthesis of claim 1, wherein the materialportion comprises a proximal portion and a distal portion and the distalportion of the material portion is more flexible than the proximalportion of the material portion.
 11. The prosthesis of claim 10, whereinthe distal portion of the material portion is electropolished, ground orchemically etched to provide flexibility.
 12. The prosthesis of claim 2,wherein the material portion comprises a first peak and a second peakand the first peak is positioned within second peak and extends in thesame plane as the second peak.
 13. The prosthesis of claim 2, whereinthe material portion includes a plurality of peaks positioned about aperimeter of the body.
 14. The prosthesis of claim 12, wherein each peakis independently operably connected to the body.
 15. The prosthesis ofclaim 1, wherein a distal end of the material portion is movableproximally in response to the retrograde pressure to facilitate openingthe valve in response to the retrograde pressure.
 16. The prosthesis ofclaim 1, wherein the distal end of the material portion is movable tofacilitate the return of the valve to a closed configuration after theretrograde pressure is removed.
 17. A method of manufacturing aprosthesis for controlling flow through a bodily lumen, the methodcomprising: forming a material portion of a valve on a first mandril;heat setting the material portion; forming an inner portion of the valveon a second mandril, the second mandril having a different shape thanthe first mandril; curing the inner portion; positioning the heat setmaterial portion on the inner portion that is positioned on the secondmandril; and coating the inner portion and the material portion to formthe outer portion of the valve.
 18. The method of claim 17, furthercomprising connecting the valve to a body to form the prosthesis. 19.The method of claim 17, comprising forming the outer portion of thevalve by dipping the inner portion and the material portion in a polymerdispersion.
 20. The method of claim 17, comprising providing a bodyhaving a first axis extending longitudinally along the body andproviding the material portion having a helical pitch that is differentfrom the first axis.